During those years he published four books: Los combatientes (1968), Galdós humorista (1969), Póker de brujas (1970), and Instantáneas al borde del abismo (1970).

Montaner began his career in journalism in 1968, working with Joaquín Maurín, a Spanish exile who had founded the American Literary Agency in New York City at the end of the 1940s with the objective of disseminating democratic ideas in the United States and Latin America.

In 1990, comments Montaner made on the television show Portada on the Univision network were perceived as offensive to Puerto Ricans.

The president of Univision, Joaquin Blaya, supported Montaner, who explained his comment in an article later published in the Wall Street Journal.

During the first half of the 1990s, the magazines Ciencia Política of Bogotá and Perfiles Liberales of Mexico City invited him to join their editorial boards, and Newsweek and The Wall Street Journal began to sporadically publish his columns.

The best-selling Manual del Perfecto Idiota Latinoamericano, in which he collaborated with Álvaro Vargas Llosa and Plinio Apuleyo Mendoza, was published in 1996 and in English in 2000 by Madison Books.

Montaner also authored No perdamos también el siglo XXI (1997) and, in 1999, Viaje al corazón de Cuba.

In the same year he was the recipient of a Premio América award by the de Centro Interamericano Gerencia Política with the inscription, "His writings on freedom have served as a guide to the oppressed and to the emerging democracies."

In 2006 Brickell Communicatios Group produced a series of 13 lessons on Cuban history for TV written and narrated by Montaner and published a collection of the scripts in the book Los Cubanos: historia de Cuba en una lección.

In 2007 two more books were published, Las columnas de la libertad and El regreso del idiota, the latter written with Plinio Apuleyo Mendoza and Álvaro Vargas Llosa.